This invention relates to the detection of an opening or closing of a closure member of an enclosure by an intruder and, more specifically, to a means for mounting the detector to the enclosure and for using Hall effect switching devices as the sensing element to detect the opening and closing.
Detecting unauthorized entrance into safes, bank vaults or protected enclosures has been a problem for many years. There are in existence today many types of devices for sensing attempts to intrude into these protected enclosures. For example, seismic detectors are included for sensing vibrations which may be caused by cutting or drilling tools, heat sensing devices may likewise be included for sensing heat generated from cutting torches or the like, and various switch mechanisms are utilized for sensing unauthorized openings.
Heretofore, such switches have been mechanical devices such as magnetically operated reed switches wherein the reed switches are attached to the frame of a doorway leading to a protected enclosure and the magnetic operator is attached to the door of the protected area. If the door is opened, the loss of the magnetic field generated by the magnet will operate the reed switches to provide an alarm. One of the problems associated with the use of such mechanical switches is that noise is generated when the contacts strike each other allowing the skilled burglar to listen to the noise and to devise a way of generating an external magnetic field so that the reed switches will not be operated when he opens the door during non-business hours. Even those reed switches which use one reed switch operated by the magnet on the door and a second normally open reed switch which will close in the presence of an external field may be defeated in this manner.
The present invention is designed to provide a silent intrusion detecting switch which can be used to detect the opening or closing of the closure member of a protected area such as the door to a safe or vault, or the door or window of a room. Moreover, the intrusion detecting switch should be mounted in such a way as to make it extremely difficult to substitute the operator of the switch by removing it from the closure itself.